How to list someone on program that could not make it due to Covid?

I would just list her normally, just as you list your other bridesmaids/wedding party. If anyone asks where she is, or even during wedding party introductions, you can still introduce her, and say that she wasn't able to attend due to COVID restrictions. You could also maybe have her on video chat for the introductions?

Honorary matron of honor. If you're doing descriptions for the other bridal party members, you could include the reason she's not there as part of hers. Also bringing her in virtually for part of the night (she can wear her dress at home) might be a nice way to include her and show her to your other guests, although I don't really know why you think they would think she's made up.

Unless everyone else is getting a write up next to their names, just list your MOH‘s name without any descriptions.

I just put an asterisk on the bridesmaid’s name in the program. One of mine can’t make it either due to covid travel restrictions.

You could add an asterisk that explains they're celebrating from afar!

“Celebrating from afar”